What is the fastest way to lvl up EggMorty into The one true Morty?

Hi guys, so I got the lvl 5 EggMorty, but I only got 1 mr. meeseeksbox. As I want the one true Morty, I woul like to lvl up my EggMorty, but I find it difficult. Especially when you cannot craft the meeseeksboxes. I was considering modding the Morty for coupons, but I don't know if that is possible or worth it in case it is possible.

I would like to know how people on here lvl up their EggMorty and what is the most efficient way to do so.

The fastest way I've found to level up Egg Morty (or any low-level Morty) is to bring them along, then only use them when you're up against a Moon/Sun/Black Hole Morty, and let them take the Implode for the team. The higher the disparity in levels between the trainer's (or wild) Morty's level and your Egg (or any other) Morty's levels, the more points they'll get, and the more levels they'll grow. I've had Mortys go up as much as a dozen levels in one hit using this method, and it's now my go to way of levelling up a very low-level Morty...just know that once you hit level 20 (or higher), Egg Morty will only turn into The One True Morty by using a level-up mega seed.

Either use the level up seeds or use a Meeseeks box on a council members mortys in the later stages of the game.